Biology 1010 - Unit 1

Levels of organization

plant, organ, tissue, cells, organelles, molecules

Cell

smallest unit that can live on its own, makes up all living organisms and tissues or the body. 1-100um in size

different types of microscopes

light, fluorescent, electron (transmission and scanning)

light microscope

use visible light and magnifying lenses

fluorescent microscope

capture fluorescence (a form of glow). can label individual molecules as they move

electron microscope

uses beams of electrons

TEM

transmission electron microscope - study internal structure of thin sections of cells

SEM

scanning electron microscope - study the fine detail of cell surfaces

what are some macromolecules?

polysaccharides, lipids, nucleic acids (DNA/RNA), proteins

what % of the cell is water? what is the rest?

70% water, the remaining 30% is varying proportions of structural and functional molecules

what are macromolecules?

lipids or polymers

how do polymers grow?

dehydration reactions

how do polymers disassemble? and to what?

to monomers by hydrolysis (meaning water breakage)

polysaccharides are…

polymers

Lipids =

not true polymers but can be large molecules

nucleic acids are…

polymers

proteins are…

polymers

carbs, proteins and nucleic acids are ____ and therefore called _____

huge - and called macromolecules

macromolecules are _____, built from ____

polymers - monomers

polymer

long molecule consisting of many similar or identical building blocks linked by covalent bonds

how are polymers linked?

covalent bonds

what do polysaccharides serve as?

fuel and building material

what molecular formula do monosaccharides have some multiple of?

CH₂O

what does a disaccharide consist of?

2 monosaccharides joined by a glycosidic linkage

what are polysaccharides?

• macromolecules

  • polymers

    • few thousand monosaccharides

• glycosidic linkages

how do plants and animals store sugars

storage polysaccharides

what do animals store?

glycogen

what do plants store?

starch (amylopectin + amylose)

what do organisms build strong materials from?

structural polysaccharides

what gives starch and cellulose distinct 3-d shapes?

differing glycosidic linkages

lipids are grouped because they share one important trait:

they mix poorly, if at all, with water

lipids are components of what?

cell membranes

what are lipids?

fats, phospholipids and steroids

fatty acids have long carbon skeletons - how many _____ atoms in length?

16-18 carbon atoms in length

what is the carbon at the end of the skeleton? what does it do? what is the rest of the skeleton?

carboxyl group (functional group that give the molecule the name fatty acid) - hydrocarbon chain

fat =

gycerol+ fatty acids

triaclycerols =

3 fatty acids + glycerol

phospholipids =

2 fatty acids + glycerol + phosphate group

saturated fat

only single bonds, solid - butter

unsaturated fat

single and double bonds - causes a kink, liquid - olive oil

polar head

hydrophilic

nonpolar tails

hydrophobic

why are phospholipids essential?

major constituents of cell membranes

steroids

lipids characterized by a carbon skeleton consisting of 4 fused rings

can cells make their own proteins?

yes

monomer of protein?

amino acids

proteins have a variety of structures, which results in what?

a wide range of functions

does protein shape matter? why?

yes - different shape = different function, everything in a cell in mediated by proteins

for what percentage do proteins account for the dry mass of most cells?

50%

what accelerates specific chemical reactions?

enzymatic proteins

antibodies are…

proteins

defensive proteins function?

protect against disease

storage proteins serve as what?

a source of amino acids

what do proteins mediate?

selective transport of substances

What is an amino acid?

organic molecule, amino group + carboxyl group + R group

proteins are made up of how many amino acids?

20 which have different physical and chemical properties

what are amino acid polymers?

polypeptides

what is the covalent bond between amino acids?

peptide bond

4 levels of protein structure

primary, secondary, tertiary, quaternary

primary structure

sequence of amino acidss

secondary structure

regions stabilized by hydrogen bonds between atoms of the polypeptide backbone

• alpha-helix or beta-pleated

tertiary structure

overall shape of a polypeptide resulting from interactions between the various amino acids

quaternary structure

2 or more polypeptide chains/subunits aggregated into one functional macromolecule

examples of quaternary structure

collagen - fibrous protein that has 3 identical helical polypeptides intertwined into a larger triple helix

• collagen is 40% of protein in the human body

hemoglobin - oxygen-binding protein of red blood cells

• heme is an iron-containing molecule bound to hemoglobin and other biological molecules

what causes sickle-cell disease?

a single amino acid substitution in hemoglobin

what do nucleic acids do?

store, transmit, and help hereditary information

2 types of nucleic acid

deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)

____ in the nucleus programs ____, in the cytoplasm by dictating synthesis of ______

DNA in the nucleus programs protein production in the cytoplasm by dictating synthesis of messenger RNA (mRNA)

nucleic acid polymer

polynucleotides

nucleic acid monomers

nucleotides

nucleotide parts

nitrogenous base, 5-carbon sugar, 1 phosphate group

2 families of nitrogenous bases

pyrimidines and purines

sugar associated with DNA

deoxyribose

sugar associated with RNA

ribose

what does deoxyribose lack in comparison to ribose?

an oxygen atom on the second carbon

what are the 2 strands of DNA made of? what do they form?

2 polynucleotides - wind around imaginary axis, forms a double helix

in what direction do the 2 sugar-phosphate backbones of DNA run?

opposite 5’ —> 3’ directions from each other

• this arrangementis referred to as “antiparallel”

RNA molecule exist as what?

single stands with complementary base pairing

base pairing withing an RNA molecule allows it to what?

take on a particular 3-d shape necessary for its function

what are the DNA base pairings?

Adenine (A) always pairs with thymine (T)

Guanine (G) always pairs with cytosine (C)

What contains DNA?

nucleus, mitochondria, chloroplast

nuclear DNA (nDNA)

the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes

mitochondrial DNA (mDNA)

circular chromosome found inside the cellular organelles called mitochondria

Chloroplast DNA (cpDNA)

he DNA located in chloroplasts, which are photosynthetic organelles located within the cells of some eukaryotic organisms

____ in the nucleus programs _____ in the cytoplasm by dictating synthesis of _____

DNA in the nucleus programs protein production in the cytoplasm by dictating synthesis of messenger RNA (mRNA).

hormonal proteins

coordination of an organism’s activities

• insulin, hormone secreted in the pancreas, causes other tissues to take up glucose, thus regulating blood sugar concentration

contractile and motor proteins

movement

• responsible for undulations of cilia and flagella

• actin and myosin proteins are responsible for the contraction of muscles

receptor proteins

response of cell to chemical stimuli

• receptors built into membrane of a nerve cell detect signalling molecules release by other nerve cells

structural proteins

support

• keratin (protein of hair, horns, feathers, other skin)

• spiders and insects use silk fibres to make their webs and cocoons

• collagen and elastin proteins provide a fibrous framework in animal connective tissues

what are the RNA base pairings?

Adenine (A) always pairs with uracil (U)

Guanine (G) always pairs with cytosine (C)

what does a procaryote lack?

true nucleus, other membrane bound organelles

nucleoid

concentrated area in a region that is not membrane-bound in a procaryotic cell

where is most of the DNA in a eukaryotic cell?

nucleus -bounded by a double membrane

how do eukaryotic cells compartmentalize their funtions?

internal membranes

what does the plasma membrane and membrane of organelle consist of?

phospholipid bilayer with various proteins attached and embedded in it

which part of a phospholipid bilayer is hydrophobic?

the interior of the membrane (where the nonpolar tails are)

which part of a phospholipid bilayer are hydrophillic?

the exteriors (polar heads in contact with aqueous solutions on either side

what may be attached to proteins or lipids on the outer surface of plasma membrane

carbohydrate side chains

what is an amphipathic molecule? example?

molecule that has both a hydrophilic and hydrophobic region

• eg phospholipid

fluid mosaic model

membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids